Can only tween objects in the workspace?

-- declarations and valuables
plr = game.Players.LocalPlayer
backpack = plr.Backpack
chr = plr.Character or plr.CharacterAdded:wait()
humanoid = chr:WaitForChild("Humanoid")
workspace.CurrentCamera.CameraSubject = humanoid
workspace.CurrentCamera.CameraType = Enum.CameraType.Custom
plrgui = plr.PlayerGui
screengui = plrgui.ScreenGui
frame = screengui.Frame
Bounce = frame.Bounce
Classic = frame.Classic
Spleef = frame.Spleef
darkerA = false
darkerB = false
darkerC = false
lobby = true
l1children = workspace.LOBBYONE:GetChildren()
l2children = workspace.LOBBYTWO:GetChildren()
l3children = workspace.LOBBYTHREE:GetChildren()
mouse = plr:GetMouse()
--gui
mouse.KeyDown:connect(function(key)
	if key == 'q' then
		frame:TweenPosition(UDim2.new(0,0,0,0) , "Out", "Quad", .2, true)
	elseif key == 'e' then
		frame:TweenPosition(UDim2.new(-.1,0,0,0) , "Out", "Quad", .2, true)
	end
end)
--classic button
Classic.MouseEnter:connect(function()
	darkerA = false
	while Classic.TextColor3.g>.4 and darkerA == false do
		game:GetService('RunService').RenderStepped:wait()
		Classic.TextColor3 =  Color3.new(Classic.TextColor3.r - .07, Classic.TextColor3.g - .05, Classic.TextColor3.b - 0)
	end
end)

Classic.MouseLeave:connect(function()
	darkerA = true
	while Classic.TextColor3 ~= Color3.new(1,1,1)and darkerA == true do
		game:GetService('RunService').RenderStepped:wait()
		Classic.TextColor3 =  Color3.new(Classic.TextColor3.r + .07, Classic.TextColor3.g + .05, Classic.TextColor3.b - 0)
	end
end)

Classic.MouseButton1Click:connect(function()
	swordremover()
	for i,v in pairs(l1children) do
		wait()
		if v.Name == "Floor" then
			local ran = math.random(1,2)
			if ran == 1 and humanoid.Health == 100 then
				chr:SetPrimaryPartCFrame(v.CFrame+Vector3.new(0,math.random(5,25),0))
				camera()
				break
			end
		end
	end
end)
-- Bounce button
Bounce.MouseEnter:connect(function()
	darkerB = false
	while Bounce.TextColor3.b>.5 and darkerB == false do
		game:GetService('RunService').RenderStepped:wait()
		Bounce.TextColor3 =  Color3.new(Bounce.TextColor3.r - 0, Bounce.TextColor3.g - .1, Bounce.TextColor3.b - .07)
	end
end)

Bounce.MouseLeave:connect(function()
	darkerB = true
	while Bounce.TextColor3 ~= Color3.new(1,1,1)and darkerB == true do
		game:GetService('RunService').RenderStepped:wait()
		Bounce.TextColor3 =  Color3.new(Bounce.TextColor3.r + 0, Bounce.TextColor3.g + .1, Bounce.TextColor3.b + .07)
	end
end)

Bounce.MouseButton1Click:connect(function()
	swordremover()
	for i,v in pairs(l2children) do
		wait()
		if v.Name == "Floor" then
			local ran = math.random(1,2)
			if ran == 1 and humanoid.Health == 100 then
				chr:SetPrimaryPartCFrame(v.CFrame+Vector3.new(0,math.random(5,25),0))
				camera()
				break
			end
		end
	end
end)
-- Spleef button
Spleef.MouseEnter:connect(function()
	darkerC = false
	while Spleef.TextColor3.b>.6 and darkerC == false do
		game:GetService('RunService').RenderStepped:wait()
		Spleef.TextColor3 =  Color3.new(Spleef.TextColor3.r - .1, Spleef.TextColor3.g - .1, Spleef.TextColor3.b - .05)
	end
end)

Spleef.MouseLeave:connect(function()
	darkerC = true
	while Spleef.TextColor3 ~= Color3.new(1,1,1)and darkerC == true do
		game:GetService('RunService').RenderStepped:wait()
		Spleef.TextColor3 =  Color3.new(Spleef.TextColor3.r +.1, Spleef.TextColor3.g + .1, Spleef.TextColor3.b + .05)
	end
end)

Spleef.MouseButton1Click:connect(function()
	swordremover()
	for i,v in pairs(l3children) do
		wait()
		if v.Name == "Floor" then
			local ran = math.random(1,2)
			if ran == 1 and humanoid.Health == 100 then
				chr:SetPrimaryPartCFrame(v.CFrame+Vector3.new(0,math.random(5,25),0))
				camera()
				break
			end
		end
	end
end)
--sword remover
function swordremover()
	local backpackchildren = backpack:GetChildren()
	local chrchildren = chr:GetChildren()
	for i,v in pairs(chrchildren) do
		if v.Name == "ClassicSword" then
			v:Destroy()
		elseif v.Name == "BounceSword" then
			v:Destroy()
		end
	end
	for i,v in pairs(backpackchildren) do
		if v.Name == "ClassicSword" then
			v:Destroy()
		elseif v.Name == "BounceSword" then
			v:Destroy()
		end
	end
end
--camera
function camera()
	workspace.CurrentCamera.CameraType = Enum.CameraType.Custom
end
workspace.CurrentCamera.CameraType = Enum.CameraType.Scriptable
workspace.CurrentCamera.CFrame = CFrame.new(workspace.Sword.Position)*CFrame.Angles(math.rad(90),math.rad(180),0)*CFrame.new(0,0,5)
--died
function menu()
	workspace.CurrentCamera.CameraType = Enum.CameraType.Scriptable
	workspace.CurrentCamera.CFrame = CFrame.new(workspace.Sword.Position)*CFrame.Angles(math.rad(90),math.rad(180),0)*CFrame.new(0,0,5)
end

humanoid.Died:connect(function()
	wait(5)
	menu()
end)

so this script is supposed to enable three buttons to change color when you mouse over them, and when you click on them they teleport you randomly. this is a local script located in starter player scripts. When I run it in studio I get an error : 20:49:38.574 - Can only tween objects in the workspace but when i play online the buttons work the first time, but after i die the tweening works but the buttons do not. they still change colors when you mouse over them but they don't teleport you when you click them. https://www.roblox.com/games/399972619/supercoolguy53s-Place-Number-122